UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

(Rule 13d-102)

Information to be Included in Statements filed Pursuant to

Rule 13d-1(b), (c) and (d) and Amendments Thereto Filed Pursuant to Rule 13d-2

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

Miragen Therapeutics, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

60463E103

(CUSIP Number)

December 31, 2017

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

*The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Persons who respond to the collection of information contained in this form are not
required to respond unless the form displays a currently valid OMB control number.

13G

ITEM 1.

(a) Name of Issuer: Miragen Therapeutics, Inc.

(b) Address of Issuer's Principal Executive Offices: 6200 Lookout Road, Boulder, CO 80301

ITEM 2.

(a) Name of Person Filing: This Statement is filed by JAFCO SV4 Investment Limited Partnership (“JAFCO SV4”) and JAFCO Co., Ltd. (“JAFCO Co., Ltd.”). The foregoing entities are collectively referred to as the “Reporting Persons.” JAFCO Co., Ltd., the general partner of JAFCO SV4, may be deemed to have sole power to vote and sole power to dispose of shares of the issuer directly owned by JAFCO SV4.

(b) Address of Principal Business Office, or if None, Residence: The address for each of the Reporting Persons is: Otemachi First Square West Tower 11F, 1-5-1, Otemachi Chiyoda-Ku Tokyo, Japan 100-0004

(c) Citizenship: The citizenship of each of the Reporting Persons is Japan

(d) Title of Class of Securities: Common Stock

(e) CUSIP Number: 60463E103

ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO SS.240.13d-1(b) OR 240.13d-2(b) OR (c), CHECK WHETHER THE PERSON FILING IS A: Not Applicable

ITEM 4. OWNERSHIP.

Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

(a) Amount beneficially owned: 667,280 shares

(b) Percent of class: 3.0%

(c) Number of shares as to which such person has:

(i) Sole power to vote or to direct the vote: 667,280 shares (See Row 5 of cover page for each Reporting Person.)

(ii) Shared power to vote or to direct the vote: See Row 6 of cover page for each Reporting Person.

(iii) Sole power to dispose or to direct the disposition of: 667,280 shares (See Row 7 of cover page for each Reporting Person.)

(iv) Shared power to dispose or to direct the disposition of: See Row 8 of cover page for each Reporting Person.

The percentages used herein are calculated based on 22,302,419 shares of Common Stock reported by Miragen Therapeutics, Inc. issued and outstanding as of November 2, 2017, as disclosed on the cover page of its Quarterly Report on Form 10-Q, as filed with the Securities and Exchange Commission on or about November 9, 2017.

ITEM 5. OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than 5 percent of the class of securities, check the following x.

Less than 5 percent owner.

ITEM 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.

Not Applicable.

ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY.

Not Applicable.

ITEM 8. IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.

See Item 2(c), Item 4 and Exhibit A.

ITEM 9. NOTICE OF DISSOLUTION OF GROUP.

Not Applicable.

ITEM 10. CERTIFICATIONS.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having such purpose or effect.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

January 30, 2018

(Date)

The original statement shall be signed by each person on whose behalf the statement is filed or his authorized representative. If the statement is signed on behalf of a person by his authorized representative other than an executive officer or general partner of the filing person, evidence of the representative's authority to sign on behalf of such person shall be filed with the statement, provided, however, that a power of attorney for this purpose which is already on file with the Commission may be incorporated by reference. The name and any title of each person who signs the statement shall be typed or printed beneath his signature.

Exhibit A

Agreement of Joint Filing

The undersigned hereby agree that a single Schedule 13G (or any amendment thereto) relating to the common stock of the Issuer shall be filed on behalf of each of the undersigned and that this Agreement shall be filed as an exhibit to such Schedule 13G.

Date: January 30, 2018